The proposed study is addressed to the need to develop an effective and efficient system to respond to the high volume of requests for services initiated by telephone, to a pediatric hospital emergency service. A key feature of the proposed system is the development of problem-oriented protocols, administered by trained health-assistants to respond to the majority of telephone requests. Protocols explicitly identify data to be collected and include guidance instructions (decision logic) on management of presenting complaints. Delegation of this clinical responsibility to persons of sub-physician levels of training is made possible through the development of standards, by which care given is monitored. Such standards are implicit in protocol construction. The first phase of the study will survey telephone requests made to the Children's Hospital Emergency Service, to note the distribution and nature of these calls, and to classify them into a discrete number of protocol-adaptable presenting complaints. Protocols will then be developed through a process which includes definition of goals, statement of qualifications and training of paraprofessionals, definition of medical content, decision-making logic and its rationale, peer review, pre-test and medical validation (medical audit). A training program will be structured around the protocol system. Implementation of the system is initiated by field-test to determine whether the system meets the majority of patient needs, and to confirm the safety, reliability and efficiency of the health assistant/protocol system. Evaluation of the system is the final arbiter of its success or failure. This will be accomplished in the second year of the study through a series of randomized clinical trials, with measures of efficiency, effectiveness and patient satisfaction as the dependent variables. The control group will be the exact "non-system" of responding to the telephone.